The use of flexible polyethylene piping in the natural gas distribution industry has offered the considerable advantage of reducing the number of valves that must be utilized in a given distribution system. In order to stop the flow of natural gas within such a pipe, the pipe is simply squeezed until its walls are collapsed against each other, thereby cutting off any flow within the pipe. Polyethylene has the capability of withstanding this kind of distortion without rupture. However, when attempting to squeeze off polyethylene piping having a diameter of 4 inches or larger, a great deal of force is required to completely close the pipe. When the pipe is cold, the required force is even greater.
The primary conventional method of performing the squeeze off operation larger diameter pipe utilizes a hydraulic cylinder and hand pump to achieve the required squeezing force. This normally requires the operator to use an expensive hydraulic system operating at high pressure (generally 10,000 psi). It would be of considerable benefit to allow large diameter pipe to be squeezed off utilizing a mechanical apparatus operated with standard equipment such as a ratchet wrench.